The present invention relates to a new and improved construction of an electrical terminal.
The terminal of the invention is of the type comprising a substantially flat housing formed of an electrically insulating material, possessing recesses or openings which open in the direction of one flat side of the housing and containing at least one clamping device for fixedly clamping at least one electrical conductor which is to be connected at the terminal. The clamping device possesses a stationary contact element and a clamping body movable by means of a clamping screw in a direction perpendicular to the contact element. The clamping body is provided with an opening or cut-out for the reception of at least one conductor which is to be fixedly clamped and into which opening or cut-out there protrudes the contact element. At the conductor infeed mouth of the opening of the clamping body there is provided a blocking flap or tongue protruding away from the contact element and serving the purpose of preventing the mistaken introduction of a conductor externally of the clamping body into the insulating housing.
With state-of-the-art terminals of this type the blocking flap or tongue is either formed of one-piece with the clamping body or by a leg of a leaf spring inserted into the opening or cut-out of the clamping body. The free length of the blocking flap must be at least as large as the displacement path of the clamping body in the axial direction of the clamping screw. This requires that the blocking flap must be relatively long if the clamping device is constructed for fixedly clamping conductors of relatively large cross-section or for fixedly clamping at the same time a number of conductors. However, with the clamping device completely loose and with increasing length of the blocking flap there is present an increasing problem of the insulation against leakage currents and voltage breakdown between the blocking flap and the metallic support rails upon which there are normally mounted the terminals. In order to avoid having to resort to too great a structural height of the terminals for the above stated reasons, something which is undesired in many instances, previously solutions were proposed wherein an insulating hose was pushed over the blocking flap, the length of which hose must exceed by a certain amount that of the blocking flap. There was thereby attained an additional advantage that due to the presence of the insulating hose there was effectively avoided undesired insertion of a conductor laterally adjacent the blocking flap. The application of such insulating hoses to the blocking flap or tongue is, however, associated with considerable work and therefore increased costs for the fabrication of the terminals. Also there is present the danger that at a subsequent period of time the insulating hose due to improper handling, or because of ignorance of the significance thereof, is mistakingly again removed.